1. Field of Invention
Apparatuses and methods consistent with the present invention relate to a light sensor which senses light using a thin film transistor, a display apparatus including the same, and a control method for the display apparatus.
2. Description of Related Art
In general, in a display apparatus including an LCD panel or an organic light emitting display panel, the luminescence of the display panel is controlled by sensing outside light. If a display panel for a handheld terminal such as a mobile phone, a PDA or a game machine is used outside or in a dark place, the appearance of an image is changed by outside light, and thus, it is very important to sense outside light.
A thin film transistor in the display panel is generally employed as a light sensor. The light sensor senses the intensity of outside light using current output from the light sensor in response to the outside light.
In the case of such a thin film transistor, output current is significantly variable by voltage between a gate terminal and a source terminal, and voltage between the source terminal and a drain terminal is also unstable due to resistance connected to the source terminal. Due to such a characteristic of the thin film transistor, it is difficult to obtain a linear output from the light sensor if the intensity of light is very low or high.
Further, if a threshold voltage (Vth) of the thin film transistor is shifted due to deterioration of the thin film transistor, variability of the output voltage becomes larger.